1. Field
The following description relates to a power semiconductor device and method of fabricating the same. The following description further relates to a high power semiconductor device such as an Insulated Gate Bipolar Transistor (IGBT) including a cell region that includes a plurality of trench structures including a dummy trench and a active trench that is configured on a semiconductor substrate and a termination region that includes a termination ring that surrounds the cell region, and thereby is operable at a high power, such as power levels corresponding to voltage levels of 600 V and 1200 V.
2. Description of Related Art
Recently, research on energy saving and high energy efficiency products and development in alternative energy sources is proceeding actively due to limitations on available energy sources. This research has led to greater interest in Smart Grid technologies, Electrical Vehicle (EV) technologies, and photovoltaic power generation technologies. Thus, the importance of a power converter that is one of the most important components in such a system is increasing. The capacity of a power converter is increasing, and thus such a power converter is being designed to bear high electricity and high voltage operation with simultaneous low on-resistance and quick response. Having these qualities accompany high efficiency and high frequency operation opens possibilities for size minimization and weight lightening when producing such a power converter.
Currently the most suitable power semiconductor device for meeting such requirements is the Insulated Gate Bipolar Transistor (IGBT). The IGBT is a three-terminal power semiconductor device primarily used as an electronic switch, which has been developed to combine high efficiency and fast switching. In such an IGBT, a low concentration drift region is formed as a thin region, and thereby reduces loss of on-resistance, and also enables a materialization of a high frequency product through concentration adjustment of a P-type collector region and control of minority carrier movement time and also enables materialization of hundreds of amperes when a high breakdown voltage of over 1200 V in the context of such a module is applied.
FIG. 1 is a cross-sectional view of an Insulated Gate Bipolar Transistor.
As illustrated in the example of FIG. 1, the illustrated Insulated Gate Bipolar Transistor includes a substrate 100, a P+ region 110, an N+ region 120, a gate electrode 130, an emitter electrode 140, a field stop layer 150, and a P+ collector layer 160.
The high concentration field stop layer 150 is used in the low concentration N-type substrate 100 to continuously decrease an electrical field by being configured between P+ collectors 110 and make the electrical field zero before the field reaches a P+ collector layer 160. Thus, in such a technology, before reaching a field stop layer 150, the electrical field is intended to be made into zero at its off-state, by using a very thick substrate, such as a substrate of 200 μm thickness. Moreover, a resistance is to be made high by making doping concentration of the substrate 100 low. In this case, due to extreme changes of a doping concentration in a substrate, switching loss is relatively large due to a thick substrate. Thus, in order to overcome such issues, use of the field stop layer 150 came into use. By using the field stop layer 150, a thickness of the substrate 100 does not have to be as thick, so it can accordingly be thinner and avoid issues that would correspond to a thicker substrate.
However, it is required to handle a thin wafer with care since a thin wafer is more fragile as substrate thickness becomes thinner. Moreover, as substrate thickness becomes thinner, features of short-circuits may develop. Useable IGBT devices that still have a high immunity against short-circuits accompanying a thin IGBT device are advantageous.